Since Theman asked for comments, I would say this:

Commercially speaking, text muds are already a failure. For something to be commercially viable, it has to make a significant profit. Are Foddy and Karya living off the proceeds of MUDII? Clearly not. They are small-audience games, but ones that are still grasping new users. Necessarily, they are run by enthusiasts, for enthusiasts.

The challenge is not their quality, which as in the case of MUDII, is unequalled in its realm, but rather in getting people to play them in the first place. Because of the nature of videogaming today, text muds, and this text mud in particular are very much newbie-unfriendly, no matter how many help files you include. The actual game is no more newbie unfriendly than any other multiplayer persistent (ish) world, but people normally stomach it in modern games because there's eye candy to distract them. In MUD there isn't - you need patience, a love of writing, a sense of adventure, or good company to make it past MUD's newbie stages. Once you're there, it's very hard to let go of the game, as the amount of ex-players that still return shows.

So are text muds commercially viable? No, and I'd say they haven't been for a while. Does that mean they're doomed to fail? No again, so long as they continue to attact the enthusiast.

IMHO, naturally :-)